Scientists claim to be a step closer to reversing the ageing process after rejuvenating worn out organs in elderly mice. The experimental treatment developed by researchers at the Dana-Farber Cancer Institute, Harvard Medical School, turned weak and feeble old mice into healthy animals by regenerating their aged bodies.

The surprise recovery of the animals has raised hopes among scientists that it may be possible to achieve a similar feat in humans – or at least to slow down the ageing process.

Antimatter atoms have been trapped for the first time, scientists say.Researchers at Cern, home of the Large Hadron Collider, have held 38 antihydrogen atoms in place, each for a fraction of a second.

Antihydrogen has been produced before but it was instantly destroyed when it encountered normal matter. The team, reporting in Nature, says the ability to study such antimatter atoms will allow previously impossible tests of fundamental tenets of physics.

For the first time, scientists believe they have witnessed the birth of a black hole. The evidence began arriving 30 years ago when a star 50 million light-years away imploded, setting into motion events that created a region where gravity is so great that nothing can escape, even light.

The initial 1979 observation of the exploding star was made by an amateur astronomer from Western Maryland, but the profession's top scientists have studied it intently with increasingly sophisticated orbiting X-ray telescopes.

Palaeontologists have identified the oldest known dinosaur embryos, belonging to a species that lived some 190 million years ago. The eggs of Massospondylus, containing well-perserved embryos, were unearthed in South Africa back in 1976.

The creature appears to be an ancestor of the family that includes the long-necked dino once known as Brontosaurus. The study in the Journal of Vertebrate Paleontology also sheds light on the dinosaurs' early development.

Scientists at the Large Hadron Collider have come the closest ever to re-enacting the beginning of the Universe – reproducing conditions a millionth of a second after the Big Bang.

Colliding particles of lead at each other at close to the speed of light, they produced heat a million times hotter than the centre of the Sun - temperatures close to those generated at the beginning of time.

Nasa's Deep Impact probe has flown by Comet Hartley 2. The first pictures revealed a roughly 1.5km-long, peanut-shaped object with jets of gas streaming from its surface. The pass, which occurred about 23 million km from Earth, was only the fifth time a spacecraft had made a close approach to a comet.

Nasa said it would take many hours to retrieve all of the data recorded by Deep Impact's two visible-light imagers and one infrared sensor. But the initial pictures to get to ground gave a fascinating view of the comet's icy body, or nucleus.

A US researcher says he plans to electronically record and interpret dreams. Writing in the journal Nature, scientists say they have developed a system capable of recording higher level brain activity.

"We would like to read people's dreams," says the lead scientist Dr Moran Cerf. The aim is not to interlope, but to extend our understanding of how and why people dream. For centuries, people have been fascinated by dreams and what they might mean. In Ancient Egypt they were thought to be messages from God.